Author: Henk Bossinade
Date: 03:44:54 08/15/04
Go up one level in this thread
On August 14, 2004 at 11:33:04, Henk Bossinade wrote:
>On August 14, 2004 at 09:19:59, Stuart Cracraft wrote:
>
>>On August 11, 2004 at 23:36:53, Robert Hyatt wrote:
>>
>>>On August 11, 2004 at 17:22:04, Stuart Cracraft wrote:
>>>
>>>>On August 10, 2004 at 13:07:21, Robert Hyatt wrote:
>>>>
>>>>>On August 09, 2004 at 14:26:18, Stuart Cracraft wrote:
>>>>>
>>>>>>Sorry, the posted position was in error. It is:
>>>>>>
>>>>>>>[D]r1bqkb1r/2pp1ppp/p1n2n2/1p2p3/4P3/1B3N2/PPPP1PPP/RNBQ1RK1 b q - 4 1
>>>>>>
>>>>>>On August 09, 2004 at 14:25:30, Stuart Cracraft wrote:
>>>>>>
>>>>>>>[D]r1bqkb1r/2pp1ppp/p1n2p2/1p2p3/4P3/1B3N2/PPPP1PPP/RNBQ1RK1 b q - 4 1
>>>>>>>
>>>>>>>I don't know if I filled in the castle flags right but in this position
>>>>>>>black still has both rights left.
>>>>>>>
>>>>>>>The question is, if your program values bishops more than knights,
>>>>>>>how do you prevent it from playing Na5 to capture the White Bishop
>>>>>>>but then giving up the pawn at e5 (since the capture Nxe4 by black
>>>>>>>is unplayable). (e.g. 1. ... Na5 2. Nxe5 Nxb3 3. ab)
>>>>>>>
>>>>>>>I've searched this to 10 full ply with unlimited quiescence
>>>>>>>and it still can't see that Na5 is bad.
>>>>>>>
>>>>>>>It would help if some people posted their searches and mention
>>>>>>>how they avoid this kind of issue.
>>>>>>>
>>>>>>>My search:
>>>>>>>
>>>>>>>Alpha=-255 Beta=245 Maxdepth=99 MaxTime=9999999
>>>>>>> 1/11> c6a5 0.00 245 68 c6a5
>>>>>>> 1/11 f6e4 0.01 1026 159 f6e4
>>>>>>> 2/15 f6e4 0.01 1008 946 f6e4 f1e1
>>>>>>> 3/17< f6e4 0.02 758 4181 f6e4 d2d4 e5d4
>>>>>>> 3/20 f6e4 0.04 75 7143 f6e4 b3d5 e4f6
>>>>>>> 4/30 f6e4 0.13 75 24970 f6e4 b3d5 e4f6 d5c6
>>>>>>> 5/34 c6a5 0.50 57 104715 c6a5 f1e1 a5b3 a2b3 c8b7
>>>>>>> 6/34 c6a5 1.22 45 256985 c6a5 f1e1 a5b3 a2b3 c8b7 b1c3
>>>>>>> 7/42 c6a5 4.31 32 889215 c6a5 f3e5 a5b3 c2b3 f8d6 d2d4 f6e4
>>>>>>> 8/51 c6a5 24.86 19 5021946 c6a5 f3e5 a5b3 c2b3 d8e7 d2d4 d7d6 e5f3
>>>>>>> 9/54 c6a5 115.27 19 19483875 c6a5 f3e5 a5b3 c2b3 d8e7 d2d4 d7d6 e5f3
>>>>>>>10/54 c6a5 264.28 26 44999682 c6a5 f1e1 a5b3 a2b3 c8b7 d2d4 f6e4 b1d2 d7d5
>>>>>>
>>>>>>>
>>>>>>>Stuart
>>>>>
>>>>>
>>>>>The output above looks broken. Why not just take the pawn. Here is Crafty
>>>>>after I play Na5 as black:
>>>>>
>>>>> 1 0.09 0.47 2. Nxe5 Nxb3 3. axb3 Nxe4
>>>>> 1-> 0.09 0.47 2. Nxe5 Nxb3 3. axb3 Nxe4
>>>>> 2 0.09 0.47 2. Nxe5 Nxb3 3. axb3 Nxe4
>>>>> 2-> 0.09 0.47 2. Nxe5 Nxb3 3. axb3 Nxe4
>>>>> 3 0.09 0.47 2. Nxe5 Nxb3 3. axb3 Nxe4
>>>>> 3-> 0.09 0.47 2. Nxe5 Nxb3 3. axb3 Nxe4
>>>>> 4 0.10 0.61 2. Nxe5 Nxb3 3. axb3 Bd6 4. d4 Bxe5
>>>>> 5. dxe5 Nxe4
>>>>> 4-> 0.10 0.61 2. Nxe5 Nxb3 3. axb3 Bd6 4. d4 Bxe5
>>>>> 5. dxe5 Nxe4
>>>>> 5 0.10 0.61 2. Nxe5 Nxb3 3. axb3 Bd6 4. d4 Bxe5
>>>>> 5. dxe5 Nxe4
>>>>> 5-> 0.10 0.61 2. Nxe5 Nxb3 3. axb3 Bd6 4. d4 Bxe5
>>>>> 5. dxe5 Nxe4 (s=2)
>>>>> 6 0.10 0.61 2. Nxe5 Nxb3 3. axb3 Bd6 4. d4 Bxe5
>>>>> 5. dxe5 Nxe4
>>>>> 6-> 0.11 0.61 2. Nxe5 Nxb3 3. axb3 Bd6 4. d4 Bxe5
>>>>> 5. dxe5 Nxe4 (s=2)
>>>>> 7 0.11 0.80 2. Nxe5 Nxb3 3. axb3 Bd6 4. d4 Bb7
>>>>> 5. f3 O-O
>>>>> 7-> 0.12 0.80 2. Nxe5 Nxb3 3. axb3 Bd6 4. d4 Bb7
>>>>> 5. f3 O-O (s=2)
>>>>> 8 0.15 0.85 2. Nxe5 Nxb3 3. axb3 d6 4. Nf3 Be6
>>>>> 5. e5 Ne4 6. d4
>>>>> 8-> 0.17 0.85 2. Nxe5 Nxb3 3. axb3 d6 4. Nf3 Be6
>>>>> 5. e5 Ne4 6. d4
>>>>> 9 0.22 0.65 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7
>>>>> 5. Nb4 Nxe4 6. d3 c5
>>>>> 9-> 0.35 0.65 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7
>>>>> 5. Nb4 Nxe4 6. d3 c5 (s=3)
>>>>> 10 0.44 0.97 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7
>>>>> 5. Nb4 Be7 6. d4 O-O 7. Nc3 (s=2)
>>>>> 10-> 0.54 0.97 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7
>>>>> 5. Nb4 Be7 6. d4 O-O 7. Nc3 (s=2)
>>>>> 11 0.70 0.78 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7
>>>>> 5. Nb4 Be7 6. d4 O-O 7. Nc3 Bb7
>>>>> 11-> 2.44 0.78 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7
>>>>> 5. Nb4 Be7 6. d4 O-O 7. Nc3 Bb7 (s=4)
>>>>> 12 3.03 0.83 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7
>>>>> 5. Nd4 Be7 6. Qf3 O-O 7. Nc3 b4 8.
>>>>> e5 (s=3)
>>>>> 12-> 6.44 0.83 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7
>>>>> 5. Nd4 Be7 6. Qf3 O-O 7. Nc3 b4 8.
>>>>> e5 (s=5)
>>>>> 13 10.00 0.88 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7
>>>>> 5. Nb4 Be7 6. Nc3 O-O 7. Qf3 Bb7 8.
>>>>> d4 Qg4 <HT> (s=4)
>>>>> 13-> 18.39 0.88 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7
>>>>> 5. Nb4 Be7 6. Nc3 O-O 7. Qf3 Bb7 8.
>>>>> d4 Qg4 <HT> (s=4)
>>>>> 14 31.39 0.82 2. Nxe5 Nxb3 3. axb3 Bb7 4. d4 Be7
>>>>> 5. f3 d6 6. Nd3 O-O 7. c4 c5 8. cxb5
>>>>> axb5 9. Rxa8 Bxa8 (s=3)
>>>>> 14-> 55.88 0.82 2. Nxe5 Nxb3 3. axb3 Bb7 4. d4 Be7
>>>>> 5. f3 d6 6. Nd3 O-O 7. c4 c5 8. cxb5
>>>>> axb5 9. Rxa8 Bxa8 (s=3)
>>>>> 15 1:28 0.80 2. Nxe5 Nxb3 3. axb3 Be7 4. d4 O-O
>>>>> 5. f3 d6 6. Nc6 Qd7 7. Nxe7+ Qxe7 8.
>>>>> Bg5 h6 9. Bxf6 Qxf6 10. Nc3 Re8 (s=2)
>>>>> 15-> 3:00 0.80 2. Nxe5 Nxb3 3. axb3 Be7 4. d4 O-O
>>>>> 5. f3 d6 6. Nc6 Qd7 7. Nxe7+ Qxe7 8.
>>>>> Bg5 h6 9. Bxf6 Qxf6 10. Nc3 Re8 (s=4)
>>>>
>>>>Black cannot play Na5 because of Nxe5 and the loss of a pawn.
>>>>
>>>>So my question was / still is, what should Black instead of Na5
>>>>if the program values Knights more than Bishops? Mine plays Na5,
>>>>gets the Bishop for the Knight and then promptly loses a center
>>>>pawn. I could decrease the value of the Bishop or increase the
>>>>value of the center pawn, but both of these seem a little extreme
>>>>given Bishop vs. Knight and the current high value of a center pawn.
>>>>The point is that a center pawn in this program is not worth as much
>>>>as a Bishop minus a Knight. The former is maybe 30 or 40 millipawns
>>>>and the latter is maybe 100 or 200 millipawns. I am looking for good
>>>>ways to avoid 1. ... Na5 in the first place.
>>>>
>>>>A knight on the rim penalty doesn't do it since the Knight is just
>>>>traded off.
>>>>
>>>>Valuing the center pawn too much makes no sense.
>>>>
>>>>I am running out of ideas to prevent 1. ... Na5.
>>>>
>>>>Stuart
>>>
>>>
>>>Why would the program "value knights more than bishops"?? firstly???
>>>
>>>Next, chess is a complex game that requires harmonious coordination between the
>>>various eval terms. Make one too big and it fails to work as planned. Or it
>>>causes other terms to appear to be too small, and making them bigger only makes
>>>things get worse.
>>>
>>>First, here is crafty in the position where you are wanting to play the knight
>>>to a5:
>>>
>>> 10 0.71 1.00 1. ... d6 2. Ng5 d5 3. exd5 Nd4 4.
>>> Re1 Ng4 5. Ne6 fxe6 6. Qxg4 Nxb3 <HT>
>>> 10-> 0.81 1.00 1. ... d6 2. Ng5 d5 3. exd5 Nd4 4.
>>> Re1 Ng4 5. Ne6 fxe6 6. Qxg4 Nxb3 <HT>
>>> 11 0.81 1.00 1. ... d6 2. Ng5 d5 3. exd5 Nd4 4.
>>> Re1 Ng4 5. Ne6 fxe6 6. Qxg4 Nxb3 <HT>
>>> 11-> 1.26 1.00 1. ... d6 2. Ng5 d5 3. exd5 Nd4 4.
>>> Re1 Ng4 5. Ne6 fxe6 6. Qxg4 Nxb3 <HT>
>>> 12 4.12 1.10 1. ... d6 2. Ng5 Be6 3. Bxe6 fxe6 4.
>>> Nxe6 Qd7 5. Nxf8 Rxf8 6. d3 Qf7 7.
>>> Nc3 Nd4 8. Bg5
>>> 12-> 19.14 1.10 1. ... d6 2. Ng5 Be6 3. Bxe6 fxe6 4.
>>> Nxe6 Qd7 5. Nxf8 Rxf8 6. d3 Qf7 7.
>>> Nc3 Nd4 8. Bg5 (s=6)
>>> 13 30.75 1.04 1. ... d6 2. Ng5 Be6 3. Bxe6 fxe6 4.
>>> Nxe6 Qd7 5. Nxf8 Rxf8 6. d3 Qg4 7.
>>> f3 Qh4 8. Be3 d5 9. exd5 Nxd5 (s=5)
>>> 13-> 50.84 1.04 1. ... d6 2. Ng5 Be6 3. Bxe6 fxe6 4.
>>> Nxe6 Qd7 5. Nxf8 Rxf8 6. d3 Qg4 7.
>>> f3 Qh4 8. Be3 d5 9. exd5 Nxd5
>>> 14 1:17 1.23 1. ... d6 2. Ng5 d5 3. exd5 Nd4 4.
>>> d6 Nxb3 5. dxc7 Qxc7 6. cxb3 Bg4 7.
>>> f3 Bf5 8. Re1 Rd8 9. Qe2
>>>
>>>
>>>
>>>Black has already played some pawn moves that leave white looking fine. Why
>>>move the knight two more times, trading three tempi for the white bishop? Black
>>>needs to develop. Develop. Develop. Not waste time chasing an unimportant
>>>bishop. Later, maybe. But if black wastes too much time, the game will slip
>>>away. The first few moves are not about bishops vs knights, because it is not
>>>yet clear which will end up being more valuable. The opening is to develop
>>>pieces first. _then_ start with other things... IE A GM will tell you that
>>>three tempi are worth a pawn. Three tempi for that bishop are hardly worth that
>>>cost...
>>
>>I realize and understand this but wonder what is the best method
>>to avoid a Na5.
>>
>>Penalize repeat opening moves by the same piece?
>>Have large rim penalties for knights?
>>Value bishops equally to bishops in the opening?
>>I'm sure it's a long list.
>
>
>I think you should simply give your engine more time.
>
>Crafty 19.1 with material eval only and BISHOP_VALUE changed
>from 300 to 330 drops Na5 and turns back to Nxe4 at depth 11.
>The same goes for my own engine.
Here's Crafty's output:
depth time score variation (1)
8 0.81 0.00 1. ... Nxe4 2. Re1 Nc5 3. Nxe5 Nxe5
4. Rxe5+ Ne6 5. Qe2 Be7
8 2.56 -0.30 1. ... Na5 2. Nxe5 Nxb3 3. cxb3 Bd6
4. Ng4 Nxe4 5. a4
8-> 2.56 -0.30 1. ... Na5 2. Nxe5 Nxb3 3. cxb3 Bd6
4. Ng4 Nxe4 5. a4
9 3.03 -0.30 1. ... Na5 2. Nxe5 Nxb3 3. cxb3 Qe7
4. d4 Nxe4 5. a4 bxa4 6. Rxa4
9-> 3.67 -0.30 1. ... Na5 2. Nxe5 Nxb3 3. cxb3 Qe7
4. d4 Nxe4 5. a4 bxa4 6. Rxa4
10 4.71 -0.30 1. ... Na5 2. Nxe5 Nxb3 3. cxb3 Qe7
4. d4 d6 5. Qc2 Bb7 6. Nc6 Qxe4
10-> 6.03 -0.30 1. ... Na5 2. Nxe5 Nxb3 3. cxb3 Qe7
4. d4 d6 5. Qc2 Bb7 6. Nc6 Qxe4
11 7.96 -- 1. ... Na5
11 14.94 0.70 1. ... Na5 2. Nxe5 Nxb3 3. cxb3 Bb7
4. d3 Ke7 5. Ng4 Nxg4 6. Qxg4 Kd6
11 22.56 0.00 1. ... Nxe4 2. Re1 d5 3. d3 Nc5 4.
Nxe5 Ne7 5. Nc6 Qd6 6. Nxe7 Bxe7
11-> 51.27 0.00 1. ... Nxe4 2. Re1 d5 3. d3 Nc5 4.
Nxe5 Ne7 5. Nc6 Qd6 6. Nxe7 Bxe7
12 1:00 0.00 1. ... Nxe4 2. Re1 d5 3. d3 Nc5 4.
Nxe5 Ne7 5. Nc6 Qd6 6. Nxe7 Bxe7 7.
Bg5
12-> 2:14 0.00 1. ... Nxe4 2. Re1 d5 3. d3 Nc5 4.
Nxe5 Ne7 5. Nc6 Qd6 6. Nxe7 Bxe7 7.
Bg5
13 2:36 0.00 1. ... Nxe4 2. Re1 d5 3. d3 Nc5 4.
Nxe5 Ne7 5. Nc6 Qd6 6. Nxe7 Bxe7 7.
Bg5 Nxb3 8. Bxe7
13-> 5:01 0.00 1. ... Nxe4 2. Re1 d5 3. d3 Nc5 4.
Nxe5 Ne7 5. Nc6 Qd6 6. Nxe7 Bxe7 7.
Bg5 Nxb3 8. Bxe7
14 7:21 0.00 1. ... Nxe4 2. Re1 d5 3. Nc3 Nxc3 4.
dxc3 Be6 5. Nxe5 Nxe5 6. Rxe5 c6 7.
Rg5 f6 8. Rh5 Kd7
14-> 13:41 0.00 1. ... Nxe4 2. Re1 d5 3. Nc3 Nxc3 4.
dxc3 Be6 5. Nxe5 Nxe5 6. Rxe5 c6 7.
Rg5 f6 8. Rh5 Kd7
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